plot bar with two colors

hello,

i want to plot my bar in two colors conditions.if Tr<0 the color is red else the color is green. Ihqve tryed this but it didn't works.

can you help me please

T=readtable('file.xlsx');
A=T{:,:};
Tr=A(:,1);
EPR=A(:,2);
for i=1:length(A)
   h=bar(Tr,EPR)
   hold on 
   if (Tr<0)
       barcolor='r';
   else
       barcolor='g'
   end
end

Answer 1

[Andy]

figure();
hold on
for i=1:length(A)
   
   if (Tr(i)<0)
       h=bar(Tr(i),EPR(i),'r');
   else
       h=bar(Tr(i),EPR(i),'g');
   end
end
hold off

[Rik]

Just a note: it is bad design to use length for matrices. It is also probably not a good idea to create many bar objects, as that many graphics objects may cause performance issues.

Answer 2

[Rik]

If you insist on separate bar objects you can use the first part, if not, you can use the second part

figure(2),clf(2)%ensure a clean figure for this example
A=rand(10,2)*5-2.5;%generate random data

Tr=A(:,1);
EPR=A(:,2);
subplot(1,2,1)
%for i=1:length(A)
for n=1:size(A,1)% or since R2020b: n=1:height(A)
    width=0.05;
    h=bar(Tr(n),EPR(n),width);
    hold on
    if (Tr(n)<0)
        h.FaceColor='r';
    else
        h.FaceColor='g';
    end
end

subplot(1,2,2)
L=Tr<0;
EPR_part=EPR;EPR_part(~L)=NaN;% this step is only require to make the bars the same width
bar(Tr,EPR_part,'r'),hold on
EPR_part=EPR;EPR_part( L)=NaN;
bar(Tr,EPR_part,'g'),hold off

[bekka mohamed]

thank you for the answer,

the code did not work well. that shows a green plot bar. and for the width, i have 2560 values so width is not necessary. i just want to plot it with two colors with a specific condition

[Rik]

Did you run my code with the generated random data, or with only your own data? This code does what you describe when I run it on R2020b. What release are you using?

[bekka mohamed]

oh, my bad ! it was a probleme with my data . so the code works perfectly thank you for your effort

[bekka mohamed]

and am using R2018b